Orderic Vitalis names him and his father. "Gauffridus vicecomes, Hugo vicecomes Castriduni, Rotrocus frater eius de Montfort" witnessed a donation to Saint-Denis de Nogent by "Henricus vicecomes Mauritanie", the charter dated to [1060] in the compilation. "Gaufridi, Hu[gonis], Rotroci, Fulcoisi filiorum meorum" consented to the confirmation of donations to Saint-Denis de Nogent by "Rotrocus castri Mauritanie comes atque Dunensis castri vicecomes" dated 11 Jan 1078. Orderic Vitalis names “...Goifredus Rotronis Moritoniæ comitis filius...” among those who took part in the battle of Hastings.
He succeeded his father in [1080] as Comte de Mortagne. "Gaufridus castri Mauritaniæ comes" confirmed donations to Saint-Denis de Nogent by charter dated [1080] in which he named "avus meus dominus Gaufridus vicecomes Castriduni et pater meus Rotrocus comes". Orderic Vitalis records that “Goisfredus Rotronis Mauritaniæ comitis filius” rebelled against Robert [III] Duke of Normandy, burnt “Excalfoium” [Echaufour], and claimed (Orderic says with justification) “Danfrontem...castrum” [Domfront] from “Rodberto cognato suo”, dated to [1088]. It appears that Geoffroy’s claim to Domfront was through his mother’s family, her grandfather having first constructed the castle. It is unlikely, therefore, that the claim by Duke Robert was based on a family connection: more likely Domfront had at some point been occupied by the duke or his father. This leaves open the precise relationship between Geoffroy and Duke Robert “cognato suo”, which has not been traced.
He adopted the title Comte du Perche after 1090. "Hugo vicecomes de Castroduno" donated the church of Saint-Léonard de Bellême to Marmoutier, with the consent of "Gausfredo comite fratre eius, Roberto Mandaguerran fratre eius, Comitissa uxore eius, Gausfredo filio eius, Matilde filia eius", by charter dated to [1092/1100].
His burial at Nogent-le-Rotrou is confirmed by the charter dated 1099 under which "Rotrocus filius domini Gauffridi comitis Mauritaniensis" confirmed donations to Saint-Denis de Nogent after returning from Jerusalem and visiting his father's tomb. 2
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